Traditional black-white bar codes encode at most a couple dozen digits. However, there exists a need for encoding several hundred to several thousand alphanumeric characters to accommodate applications such as the labelling of semiconductor packages or credit card labelling, as well as labelling sight, sound or software media. Thus in general there is a need for item or package labelling in which large amounts of information can be provided in label form. Note, bar codes are relatively large and, even so, bear very little information. Moreover, bar code labels are commonly read using simple hand held scanners. Thus, bar codes are better when used where very little information is to be conveyed.
There do exist denser information storage matrices utilizing small black/white dots or stripes, such as made by Verotec Inc. of Chatsworth, Calif., or Symbol Technologies Inc. of Bohemia, N.Y., or Intermec Corp. of Lynnwood, Wash. There also exist very dense optical information storage techniques involving CD ROM and holography. However, there is still a requirement for further simplified high density storage as well as a requirement for visual interrogation by simplified optical means.
Colored bar arrays bearing encoded information have been used for many years for instance for color coding of electrical and electronic resistors. In all cases these arrays make use of bars whose colors appear unique to the human eye. No attempt was ever made to create bars using the same color but differing only in intensity as the coding factor to be solely machine read. The basic reason was the unavailability up to the current state of the art of reliable and relatively inexpensive mechanisms such as solid state cameras, computers, software programs, and Application Specific Integrated Circuits to create low-cost readers that could discern and discriminate intensities as well as colors. By way of background, U.S. Patents illustrating black and white and colored bar codes include U.S. Pat. Nos. 3,772,200, 3,858,506, 3,861,886, 4,010,355, 4,044,227, 4,053,433 4,239,261, 4,329,393, 4,390,452, 4,794,238, 4,268,179, 5,003,251, 4,855,909, 4,844,509, 4,714,934.
As will be appreciated, none of these systems are sufficiently information dense to provide for instance as much as 3000 Mbytes of information within a small labelling area.
Applications for such an information-dense labelling system can be found potentially in most every aspect of the marketplace. The inexorable trend to computerization in all activities leads inescapably to the necessity for information-dense labels and other information storage media. Simply put, for certain applications there is a necessity for the encoding and optional encryption of all relevant information pertaining to the product, which information follows the product for the life of the product.
As an example of the use of small information dense microlabels, these labels may be affixed to a component part in a machine, where the microlabel provides not only an ID number, but sufficient information to reconstruct the manufacturing drawing, the quality of the component as inspected prior to labelling, notes of importance to field service, maintenance information and information regarding final disposal. As can be seen, an appropriate microlabelling system can decrease machine downtime due to faulty components by solving the all too frequent inability to identify the proper component or find a replacement even if it must be made from scratch.
A second example for the use of such a microlabel is the so-called SmartCard, which requires basic machine readable information that is not alterable such as account numbers, ownership information, identification information, basic credit line, issuer, contract and communication data. Moreover, it is essential that the information be secure and unalterable. What is needed is WORM (Write Once Read Many Times) technology. In this regard, magnetic strips or other alterable Random Access Memory type devices are not acceptable because of alterability.
A third example for the use of information dense microlabels is to defeat sales of counterfeit and pirated sight and/or sound recordings, and data media. In this application each CD, tape, record, film, diskette, or any media item receives a unique microlabel, with each label printed independently for each item, and bearing encoded information which uniquely identifies the product in great detail. Even if hundreds of thousands of copies are published of a specific item, each copy is made to bear a uniquely different code, thus impeding the counterfeiting by simple methods.